WO 2006 018 614 A1 discloses a replaceable flow assembly for use in a water cooler or similar bottled liquid dispenser. The flow assembly includes a liquid reservoir and a manifold incorporating a bottle connector for releasable sealing engagement with a neck formed on an inverted bottle. The manifold is mounted on the reservoir and incorporates a first pathway for conducting liquid from the bottle connector to the reservoir, and a second pathway for conducting liquid from the reservoir to a discharge outlet. A third pathway within the manifold conducts atmospheric air through an air filter and into the interior of the bottle through the delivery tube without passing through the reservoir. In a preferred embodiment the flow of liquid is assisted by an impeller which is incorporated in the manifold magnetically coupled to an external motor. Another embodiment is also described in which an external air pump pressurizes the bottle via the third pathway.
Bottled liquid dispensers also frequently include a hot tank which receives ambient water from the bottle and which incorporates a heating element to provide a supply of hot water at a separate discharge outlet. Water may leave the hot tank via a steam valve which automatically vents gases to prevent a dangerous pressure build-up.
In common with most contemporary water coolers, which are often referred to as “top loaders”, the bottle has to be inverted and lifted onto the top of the cooler. WO 2003 062 131 A1 discloses a water cooler in which the bottle does not need to be inverted and is placed in the bottom of the cooler—therefore known as a “bottom loader”. A liquid pump draws water from the bottle via a non-return valve. In one embodiment a passage with a flow restriction bypasses the non-return valve to prevent over-pressure in the system.
Replaceable flow assemblies as in WO 2006 018 614 A1 permit quick and easy sanitization of the water cooler by replacing the water contacting surfaces in a single operation. In bottom loaders however, the need to maintain adequate dispensing pressures makes it more difficult to provide a low cost and easily replaceable flow assembly. Furthermore, tortuous flow paths and complex valve arrangements can reduce flow rates and produce undesirable heat transfer to or from the various flow paths.
Various problems have been encountered with replaceable flow assemblies. Firstly, during replacement of the flow assembly there may be a tendency for water to spill out of the water inlet. A second problem is that in some circumstances the steam valve may permit the hot tank to siphon back into the bottle and empty. In bottom loaders a non-return valve and pressure relief valve may be included in the flow path from the bottle, but this adds to the cost of the assembly, and if the valves should fail back-siphoning can still occur. Another problem which has been encountered is that the cold reservoir does not always fill consistently. Ideally the unit will prime consistently and automatically when the flow assembly has been changed.